This invention relates to external bone fixators for setting fractures of the human skeleton. In particular, this invention relates to a modular bone fixator assembly for setting fractures of the distal radius and other bones. This invention improves upon the earlier inventions described in U.S. Pat. Nos. 6,056,748 and 6,283,964, both entitled MODULAR FIXATOR ASSEMBLY, which are incorporated herein by reference.
The prior art is replete with external bone fixator devices which are used for setting various bone fractures. Many external bone fixator devices employ transcutaneous pins (e.g., K-wires), stakes, screws or other types of bone fasteners, which are secured in the bone on opposing sides of the fracture. The pins are then secured to an external splint device. The external splint device may use various articulations to adjust its position relative to the bone fasteners. During the fixation surgery, the bone pieces at the fracture may be realigned by the surgeon. The various articulations in the external splint device may assist the surgeon in realigning the bone pieces. Once the external splint device is secured to the bones and the bone pieces are in the desired alignment positions, the articulations in the fixator are locked in place to maintain the bone alignment for a healing duration.
Some of these external bone fixator devices are especially adapted for repairing fractures of the distal radius. This type of fracture often involves a fracture site close to the distal head of the radius. Fractures of the distal head of the radius are commonly referred to as Colles' fractures. Such fractures may be reduced using bone fasteners set on the distal side of the fracture in the metacarpal bone and bone fasteners set on the proximal side of the fracture in the distal half of the radius.
It has been recognized that it is desirable for the wrist to have a certain degree of mobility during the treatment of wrist fractures. However, prior art fixator devices which employ longitudinal traction applied by proximal and distal pins generally do not allow motion at the wrist without crossing the joint during the period of fracture immobilization.
Accordingly, there is a substantial need for improved external fixator devices. The fixator devices need to be strong, rigid and durable, to withstand any forces or inadvertent blows to which the fracture sight is subjected. The fixator devices must be lightweight, so as to movable by the patient without extreme difficulty. The fixator devices should be reasonable in manufacturing cost and difficulty. The fixator devices should facilitate a wide range of surgical techniques, to permit the surgeon to best adapt to the particular fracture and to provide the best mode of healing. In particular, the surgical techniques facilitated by the fixator device should allow the surgeon to quickly reduce the fracture during surgeon while still providing the support needed during the healing duration.